The issue in this appeal is whether property owned and operated by the appellee, Opportunities, Inc., is entitled to exemption from ad valorem taxes imposed by the appellant, Miller County. The property consists of land upon which there is an apartment complex occupied by persons aged 55 and older. Exemption was denied by the Miller County Court. That decision was reversed on appeal to the Miller Circuit Court which held that the property falls within the exemption provided in Ark. Const. art. 16, § 5(b), i.e., “Buildings and grounds . . . used exclusively for public charity . . . .” It was also held that prior rulings granting exemption with respect to the property in question barred reconsideration of the issue. We hold that the record does not demonstrate that the property is used exclusively for public charity and that the prior rulings to which the Circuit Court adverted have no res judicata, collateral estoppel, or law-of-the-case effect. We, therefore, reverse the decision.
1. Exemption
The burden on a party claiming a constitutional tax exemption is to prove entitlement beyond a reasonable doubt. City of Fayetteville v. Phillips, 306 Ark. 87, 811 S.W.2d 308 (1991). Tax exemption provisions must be strictly construed against exemption, and if there is any doubt, the exemption must be denied. Pledger v. Noritsu America Corp., 320 Ark. 371, 896 *92S.W.2d 595 (1995). As in the Pledger case, there is no factual dispute here.
Patty Smith, the Director of Opportunities, Inc., testified that the formal criteria for admission to Meadowbrook Place include “financial resources to meet the monthly fee.” There is nothing in the record to the contrary. Ms. Smith said that no one had been turned away from Meadowbrook Place due to inability to pay, and she had not been authorized by her board of directors to do so. She testified, however, that an applicant who has difficulty meeting the monthly fee covering rent, meals, utilities, and other services is counseled in an effort to find sources of funds to meet the fee. If sources cannot be found, the applicant is referred to another program. All Meadowbrook Place residents pay a monthly fee. The average fee is $650.00. There is nothing in the record to suggest that Opportunities, Inc., pays any part of any resident’s monthly fee at Meadowbrook Place, although the organization subsidizes the operation to a certain extent and uses some of the Meadowbrook Place facilities in support of its other charitable activities.
In cases involving hospitals run by not-for-profit organizations, beginning with Hot Springs School Dist. v. Sisters of Mercy, 84 Ark. 497, 106 S.W. 954 (1907), we have held that the admission of paying patients does not destroy the tax-exempt status of the hospital property. Sebastian Cnty. Bd. v. The Western Ark. Counseling and Guidance Ctr., 296 Ark. 207, 752 S.W.2d 755 (1988). In Hot Springs School Dist. v. Sisters of Mercy, supra, the Sisters of Mercy were operating a hospital and pharmacy dispensing care and medicine to paying and nonpaying patients. Those who could not pay were treated and received medicine free. Fees paid by the paying patients were devoted solely to helping pay for the treatment and medicine received by those who could not pay. We wrote: “The fact of receiving money from some of the patients does not, we think, at all impair the character of the charity, so long as the money thus received is devoted altogether to the charitable object which the institution is intended to further.”
To qualify for the exemption, a hospital must be a place where no one may be refused services on account of inability to *93pay, and where all profits from paying patients are applied to maintaining the hospital and extending and enlarging its charity. Burgess v. Four States Memorial Hosp., 250 Ark. 485, 465 S.W.2d 693 (1971).
In the case now before us, we have evidence that Opportunities, Inc., has lost money on its operation of Meadow-brook Place, but we have no showing that any charitable activity is occurring there or that the fees paid by the residents are being devoted to a charitable purpose. Applying the hospital cases by analogy, Meadowbrook Place does not qualify for the exemption. Although it has not turned an applicant away due to inability to pay its fees, it is clear that its policy requires that the fees be paid and that an applicant may be refused if he or she is unable to pay. Although help is provided in finding sources for payment, payment is required.
2. Previous rulings
In addition to Ms. Smith’s testimony, the Trial Court also considered three prior orders dealing with the immunity of Meadowbrook Place. A September 27, 1989 order, entitled “County Court Order,” signed by the county judge, a circuit judge, and the county assessor, ordered that the 1988 taxes on Meadowbrook Place be waived based on the warranty deed which conveyed Meadowbrook Place and on information from the county assessor.
On June 18, 1990, a tort action was filed against Meadow-brook Place, and the Miller Circuit Court dismissed the action on the basis that Meadowbrook Place was a charitable institution entitled to charitable immunity.
On October 28, 1991, a hearing was held before the Miller Chancery Court based on a Petition for Tax Exemption by Opportunities, Inc. The Chancelor found that Opportunities, Inc., was a tax-exempt organization in its operation of Meadow-brook Place and removed Meadowbrook Place from the tax rolls. The Chancellor also ordered that the tax collector of Miller County not collect any taxes assessed on the property for prior years. On December 19, 1991, the Chancellor, after hearing the *94motion of the prosecuting attorney, set aside the October 28 order and then set the matter for a hearing. There is no indication in the record of this case that a hearing was held.
In the case now before us, the Circuit Court, applying the doctrines of res judicata, collateral estoppel, equitable estoppel, and law of the case, held that further consideration of the issue of taxation of the Meadowbrook Place property was barred.
a. Res judicata
The claim-preclusion facet of res judicata bars relitigation of a subsequent suit when: (1) the first suit resulted in a final judgment on the merits; (2) the first suit was based upon proper jurisdiction; (3) the first suit was fully contested in good faith; (4) both suits involve the same claim or cause of action; and (5) both suits involve the same parties or their privies. Griffin v. First National Bank, 318 Ark. 848, 888 S.W.2d 306 (1994).
The September 27, 1989 order, signed by the county judge, a circuit judge, and the county assessor, is most unusual. It contains no reference to any proceedings upon which it was based. We hold it is not entitled to res judicata effect because it is not known which court, if any, rendered it. There is no indication that Miller County was a party to the order or to any proceedings giving rise to it. There is, indeed, no evidence that the order was the result of any kind of suit or that the suit was “fully contested.”
The October 28, 1991 chancery order has no res judicata or other effect because it was set aside, apparently because the chancery court lacked jurisdiction. See Ark. Const. art. 7, § 28, which vests exclusive jurisdiction in the county courts with respect to all matters relating to county taxes.
The December 7, 1990 court order has no res judicata effect in this case because the underlying tort action did not involve the same claim or cause of action, and Miller County was neither a party nor in privity with any of the parties to the tort action.
*95 b. Collateral estoppel
The following elements must be shown in order to establish collateral estoppel: (1) the issue sought to be precluded must the same as that involved in the prior litigation; (2) the issue must have been actually litigated; (3) the issue must have been determined by a final and valid judgment, and (4) the issue must have been essential to the judgment. Hill v. State, 331 Ark. 312, 962 S.W.2d 762 (1988).
The September 27, 1989 order does not bar a holding against Meadowbrook Place based on collateral estoppel because there is no indication that any issue was actually litigated, and there is some question as to whether the order constitutes a final and valid judgment.
The December 7, 1990 order does not bar a holding against Meadowbrook Place based on collateral estoppel because the issue in the two cases is not the same.
The October 28, 1991 order does not bar a holding against Meadowbrook based on collateral estoppel as the order was set aside.
c. Law of the case
The doctrine of law of the case prevents an issue raised in a prior appeal from being raised in a subsequent appeal unless there is a material variance in the evidence before the court in each appeal. Fairchild v. Norris, 317 Ark. 166, 876 S.W.2d 588 (1994). The doctrine is, however, not limited to issues raised in prior appeals as it was developed to maintain consistency and avoid reconsideration of matters once decided during the course of a single continuing lawsuit. Id.
The September 27, 1989 order does not bar a holding against Meadowbrook based on law of the case because the order was not part of this lawsuit, and there is no indication that Miller County was a party in that suit.
*96The December 7, 1990 order does not bar a holding against Meadowbrook based on law of the case because the tort action is not part of this lawsuit.
The October 28, 1991 order does not bar a holding against Meadowbrook based on law of the case because the Chancellor set aside the order.
d. Equitable estoppel
As to the doctrine of equitable estoppel, we recognize four necessary elements: (1) the party to be estopped must know the facts; (2) the party to be estopped must intend that his or her conduct be acted on or must so act that the party asserting the estoppel had a right to believe it was so intended; (3) the latter must be ignorant of the true facts; and (4) must rely on the former’s conduct to his or her injury. Foote’s Dixie Dandy v. McHenry, Adm’r, 270 Ark. 816, 607 S.W.2d 323 (1980).
Opportunities, Inc., argues that Miller County should be estopped from arguing that Opportunities, Inc., is not tax exempt based on the prior orders. Meadowbrook Place further argues that “the purpose and use of the property was discussed with the City of Texarkana, Arkansas, in securing the deed to the property and with officials of Miller County shown on the referenced orders finding the right to the tax exemption for charitable purposes of this property.”
There is no indication that Meadowbrook Place relied on actions or statements by an agent of Miller County. The September 27, 1989 order was signed by the tax assessor; however, it only stated that the 1988 taxes were waived. Ms. Smith did testify that Opportunities, Inc., discussed its intended use of Meadow-brook Place with the City of Texarkana, Arkansas, with the Miller County Judge, the Miller County Tax Assessor, and a Miller County Circuit Judge; however, she does not indicate that any agent of Miller County guaranteed tax exempt status or that Opportunities, Inc., relied on such statements in purchasing and developing Meadowbrook Place. There is no indication in the abstract that Opportunities, Inc., purchased Meadowbrook Place *97in reliance upon any statement by an agent of Miller County that the property would be tax exempt based on charity status.
Reversed and remanded.
Corbin and Thornton, JJ., not participating.
Special Justice Martha Miller Harriman joins in this opinion.
Chief Justice Arnold and Special Justice Jim H. Boyd dissent.